MOREHEAD CITY – Researchers at University of North Carolina Institute of Marine Sciences began more than a year ago tracking in wastewater the virus that causes COVID-19, just as the pandemic was beginning to sweep across the globe.
That research led to the lab to start testing samples from 11 wastewater treatment plants in the state earlier this year for the North Carolina Department of Health and Human Services, the results of which are on the NC COVID-19 Dashboard. Plans are to boost sampling to 20 plants starting next month.
Dr. Rachel Noble, a professor who studies environmental microbiology and marine microbial ecology at UNC-IMS, directs the lab there researching SARS-CoV-2, the virus that causes COVID-19, in wastewater.
Symptomatic and asymptomatic people with COVID-19 shed viral particles in their feces. Though no longer infectious in wastewater, the viral particles can be measured if enough people are infected, according to the state Department of Health and Human Resources. With one sample, trends in an entire community that uses the same sewer system can be identified, which can supplement existing COVID-19 data. Wastewater monitoring does not detect COVID-19 vaccines because the vaccine does not contain SARS-CoV-2.
“Wastewater offers you an ability to look at the whole population, rather than just the people that are getting tested. And we see that the wastewater pretty much matches the clinical cases, but not always,” Noble told Coastal Review, adding it shows there’s a good value in doing the wastewater work. “Wastewater allows you to kind of get an overall view of your community.”
Noble was a lead researcher for a project through the North Carolina Policy Collaboratory to track SARS-CoV-2 in North Carolina wastewate in the latter half of 2020. The Center for Disease Control and Prevention then tapped the state Department of Health and Human Resources to test wastewater samples as part of its National Wastewater Surveillance System, a tool to better understand COVID-19 infections in communities.
Wastewater samples for the CDC have been tested in Noble’s lab since the start of the year. The state announced May 21 that the NC COVID-19 Dashboard had been expanded to include wastewater monitoring. The COVID-19 Dashboard shows the state’s testing, tracing and trends.
The statewide program, North Carolina Wastewater Monitoring Network, is a collaboration of DHHS, UNC researchers, 11 wastewater utilities and eight public health departments.
Noble said her lab has been testing twice a week since January samples from the 11 facilities, which are located in Wilmington, Beaufort, south Durham, New Hanover County, Chapel Hill-Carrboro, Raleigh, Pittsboro, Newport, Greenville and two in Charlotte.
Starting July 1, analysis will expand to 20 locations, including in the northeastern and northwestern parts of the state, which Noble said had not been covered.
The initial 11 sites have a university within the vicinity. Noble said this was intentional to facilitate the research. Academic partners were asked to contact their nearby wastewater treatment plants — many already had working relationships with wastewater facility staff — making it easier to collect samples.
A benefit to this project is being able to collaborate and build connections with both the state and municipal stakeholders. The sewage treatment plants are in towns all over the state and Noble said they’ve met with people with local knowledge who can talk about the local culture, know what to do when big storms hit, and even when tourists are in town.
She gave as an example a wastewater system on the coast. She said the amount of flow into the sewage system Monday through Friday, compared to Saturday and Sunday in the summer is “obnoxious” because of the influx of visitors. This could be due to visitors taking longer showers or using the dishwasher more. “It’s really amazing. It’s learning a lot about the dynamics of the town through something that’s really basic. It’s a basic service.”
Noble told Coastal Review that her lab was one of the first in the country testing viral pathogens in wastewater and stormwater when COVID-19 hit early last year.
Her lab manager suggested that they begin testing for SARS-CoV-2 in late February 2020. The lab already was studying viruses, so testing for coronavirus was a matter of adding a different type of reagent, or chemical compound, to the analysis. “It was a really easy switch.”
Noble’s lab was approached in the spring of 2020 to develop the statewide surveillance program funded by the North Carolina Policy Collaboratory.
The final report, “Tracking SARS-CoV-2 in the Wastewater Across a Range of North Carolina Municipalities” dated Feb. 8, 2021, states that the collaborative effort of the UNC system, state agencies like the departments of Health and Human Services and Environmental Quality, and water utility stakeholders “has successfully built the foundation and capacity for the State of NC to not only conduct, but to lead the development of, wastewater-based surveillance in the broadest sense.”
The Center for Disease Control and Prevention contacted the Department of Health and Human Services to participate in the CDC’s National Wastewater Surveillance System. Noble said that because her lab had the capacity, DHHS asked her to take on the project.
North Carolina is one of eight pilot states in the CDC National Wastewater Surveillance System developed to provide information on the presence and persistence of SARS CoV-2-like viruses in wastewater systems as a metric of community COVID-19 prevalence, the report states. The surveillance program coordinated with the CDC was to develop an early warning system not dependent on clinical testing of COVID-19-infected individuals.
Noble said there were a number of surprises that she came across during her research, including getting a SARS CoV-2 signal in June and July 2020 in Beaufort’s wastewater treatment system, which serves about 4,000 people.
“That surprised me, because at the time, the number of described cases in Carteret County was really low,” she explained. Adding that either people were coming into town as tourists or there actually was illness in the community that wasn’t getting tracked.
The second thing that surprised her was how quickly groups without any previous experience with that kind of work were able to get up and running. A group at University of North Carolina Wilmington was engaged in molecular work on other types of viruses but were able to switch over, with some help from her technicians on how to process samples, and were able to switch seamlessly to processing samples for the coronavirus.
There are limitations to this type of COVID-19 monitoring, according to the state. Around 40% of the state’s population uses septic systems for wastewater. Even if all wastewater treatment plants statewide were being tested, the data would represent six out of 10 people in the state. Also, scientists are still researching how long SARS-CoV-2 shedding occurs and what proportion of people with COVID-19 shed the virus in their feces.
“Wastewater monitoring is a new tool that will help us track the spread of COVID-19 in participating communities even as fewer people are being tested,” said state epidemiologist Dr. Zack Moore in a statement. “This can be an early warning system and allow health officials to take actions to stop the spread if trends are increasing.”
If wastewater data show an unexpected increase in COVID-19 in a community, the state will notify the wastewater treatment plant and health department. The information then can be used by officials to organize or increase pop-up testing and increase public health communications on the importance of masking, handwashing, social distancing and avoiding large crowds in enclosed spaces, according to the release.
Officials can also alert area hospitals, clinics and other health care providers about a potential increase in cases and provide recommendations to community leaders or implement restrictions like limiting indoor gatherings and reducing business capacity; and take steps to increase vaccination in the community.